A new critical vulnerability in the Ruby on Rails (“Rails”) web application framework, CVE-2026-66066, could turn a seemingly innocuous image into a front door to your secrets.
Disclosed July 30, the high severity CVE (scored 9.5 out of 10) poses a significant risk to enterprises running apps that handle user-uploaded images in Rails.
Dubbed “KindaRails2Shell,” it targets the overly-trusting Active Storage component of the open-source framework, allowing unauthenticated attackers to read sensitive files or escalate to remote code execution (RCE).
The issue has been fixed in versions 7.2.3.2, 8.0.5.1 and 8.1.3.1 of Active Storage; enterprises running Rails should update immediately.
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